The overarching goal of this time-sensitive application is to measure the effectiveness of the new abuse deterrent formulation (ADF) for OxyContin(R) in decreasing abuse of OxyContin(R). Prescription opioid abuse is a major public health concern and has plagued the rural United States in particular. The Office of National Drug Control Policy (ONDCP) and the FDA have strongly encouraged the pharmaceutical industry to develop formulations that protect against abuse; however, apart from clinical trials among pain patients demonstrating efficacy of the drug for treating pain, there have been no epidemiologic studies to date that have examined whether ADFs are actually effective in reducing abuse of any drug. A longitudinal epidemiologic study of prescription opioid abuse is currently in the latter phase of follow-up in rural Kentucky (R01-DA024598) in which 94.8% of participants abused OxyContin(R) in their lifetime, and 81% abused the drug in the 6-months prior to the formulation change. Given this high prevalence of OxyContin(R) abuse before the formulation change, this study sample is ideal for detecting changes in signals of abuse with the new ADF for OxyContin(R). The specific aims include: 1) evaluation of the effectiveness of the ADF for OxyContin(R) in reducing abuse via oral, intranasal and injection routes; 2) determining whether opioid users transitioned to abuse of other prescription opioids once the non-ADF version was no longer available on the street; and 3) examination of changes in prevalence and incidence of HIV and hepatitis C (HCV) as a result of changes in route of administration after the old formulation was no longer available. This time-sensitive study is highly significant given the paucity of epidemiologic data related to the effectiveness of ADFs in reducing abuse of prescription opioids. Further, this study is uniquely positioned to measure the effectiveness of the ADF for OxyContin(R) expeditiously and without the potential bias that would result if abuse were assessed retrospectively. Given the importance that the ONDCP and the FDA have placed on further development of ADFs for prescription opioids, the results from this study have vast implications for public policy in addition to public health. This highly relevant study will evaluae the effectiveness of a model ADF across multiple public health domains, including changes in this product's abuse and misuse via the oral, intranasal and injection routes of administration. The results from this study, in turn, will have vast implications for not only public health, but aso policies surrounding development of ADFs in order to prevent abuse of prescription opioids.